Review NITECORE P20i UV - White and UV light - 1800 lumens

Well-known member
Dec 3, 2012

I received the Nitecore P20i UV directly from Nitecore for the review.
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The Multilingual Manual: is external)

Nitecore with the new P20i UV updates its tactic with UV LEDs by successfully entering the Nitecore i-Generation system, thus joining the P20i and P20iX.
The P20i UV uses the same form factor as the P20i, it changes the length which is slightly higher (150.5mm) while maintaining the maximum brightness of 1800 lumens. The Nitecore P20i UV has 2 modes: tactical and daily mode. It is rechargeable via the fast USB-C port and uses a 21700-format lithium battery patented by NITECORE (4,000mAh NL2140i). Like the previous P20i, also the P20i UV is a purely tactical flashlight with two switches in the queue; one equipped with “STROBE READY” technology with quick activation of the Strobo. The beam of the P20i UV reaches 337 meters for over 28,500cd. Nitecore P20i UV is equipped with a Luminus SST-40-W LED (6500K) and 4 UV LEDs (320mW with wavelengths of 365nm), has 4 light levels (High, Medium, Low and UV) plus the special level Strobe and can also be powered by two CR123 / RCR123 batteries via the adapter included in the package. The P20iUV is IP68 certified (submersible up to 2 meters) with an impact resistance of 2m.
The Nitecore P20i UV is an ideal complement for law enforcement, assault, self-defense, search and patrol operations.


  • The white light utilizes a Luminus SST-40-W LED with a max output of 1,800 lumens
  • The UV light utilizes 4 x UV LEDs (320mW, wavelength 365nm)
  • An optical system combined with crystal coating and “Precision Digital Optics Technology" (PDOT)
  • Highly efficient constant current circuit provides a stable output for up to 50 hours
  • Dual tail switches enable intuitive operations for tactical applications
  • STROBE READY™ Technology to enable a quick access to STROBE Mode
  • STROBE Mode uses randomly changing frequencies for stronger dizzying effects
  • Tactical Mode and Daily Mode available
  • Intelligent Li-ion battery charging circuit with a USB-C port
  • NITECORE 21700 Li-ion battery included (NL2140i 4,000mAh)
  • A power indicator beside the charging port indicates the remaining battery power
  • The power indicator can display the battery voltage (±0.1V)
  • Strike bezel uses high strength silicon nitride ceramics to enable excellent glass breaking performance
  • Incorporated Advanced Temperature Regulation (ATR) module
  • Optical lenses with double-sided scratch resistant coating
  • Constructed from aero grade aluminum alloy
  • HA III military grade hard-anodized finish
  • Waterproof and dustproof rating in accordance with IP68 (2 meters submersible)
  • Impact resistant to 2 meters


Length: 150.5mm (5.93") Head Diameter: 31.8mm (1.25") Tube Diameter: 25.4mm (1") Tail Diameter: 28.5mm (1.12") Weight: 124g (4.37oz)


NITECORE 21700 Rechargeable Li-ion Battery (NL2140i 4,000mAh), Tactical Holster NTH20, Clip, Lanyard, Spare O-ring, CR123 Battery Magazine, USB-C Charging Cable


Nitecore P20i UV comes in the classic black cardboard box with yellow lettering. The main features that distinguish the new Nitecore are shown on the sides of the box. Inside the package, in addition to the Nitecore P20i UV with the Nitecore NL2140i battery inserted, we find the Clip, the NTH20 tactical holster, the USB-C charging cable, the adapter for CR123 / RCR123, the lanyard, an O-ring of parts, manual and warranty.


With the Nitecore P20i UV instead of the classic cordura holster, the NTH20 tactical holster is given. This black rigid plastic accessory allows you to extract and store the flashlight faster and safely using 4 adjustment points based on the width of the belt. It also allows the complete use of the P20i UV even if inserted inside it as well as being compatible with the "MOLLE" system.

Nitecore P20i UV is built with the usual quality standards to which Nitecore has accustomed us. Excellent finishes as well as the writings that are clearly legible. Although longer than the P20i, the new Nitecore UV flashlight remains compact and easily manageable with the hand. Its length is 150.5 mm with a well-structured design and shape that allow excellent grip in the hand. It is built in aluminum alloy with an anodized finish, well made, in a glossy black color with a weight of 124 grams (without battery). The P20i UV consists of two parts: head with body and tail. Note the particular shape of the base of the head (hexagonal) which avoids rolling. Due to the very protruding main button of the P20i UV, the flashlight cannot be placed upright (candle-shaped).

On the head of the Nitecore P20i UV we find a SMO dish with the central LED Luminus SST-40-W (6500K) and 4 lateral UV LEDs (320mW with wavelengths of 365nm). Glass and parabola have anti-reflective, crystal coating and PDOT (Precision Digital Optics Technology) treatment. Nitecore P20i UV is equipped with an aggressive bezel (Strike Bezel) with 3 high hardness silicon nitride ceramic balls that allow quick and easy use for personal defense or for breaking a glass.

In the P20i UV the cooling fins increase by one unit, certainly made possible by the greater length of the head.

Also on the head we find the charging port in USB-C format protected by a very thick rubber flap and the notification LED. The base of the hexagonal shaped head allows the torch not to roll.

To recharge the Nitecore P20i UV, just use the supplied USB cable, connecting it to an external power source (e.g. a battery charger for mobile phones or tablets, a PC or any other compatible power system) to begin the charging process.
During the charging process, the blue charge indicator will flash slowly; when the battery is fully charged, the P20i UV will cease the charging process and the charge indicator light will stay on steadily.
The charging time for a 21700 (4,000mAh) Li-ion battery found in my tests is approximately 3 hours and 45 minutes (using a 5V / 2A power supply). When the Nitecore P20i UV is charging it cannot be used.

The blue notification LED also acts as a remaining charge indicator; when we insert a battery in the flashlight, the indicator will flash to indicate the state of charge of the battery while when it is about to run out of charge, the LED warns us with a quick flash.

The central body of the Nitecore P20i UV has a rhomboid-shaped non-slip knurling with the space in the center to insert the given Clip supplied with the flashlight.
Sold separately we find other interesting accessories such as the Tactical Ring Pro.

Below the central tube are the threads which are anodized and well lubricated. By slightly unscrewing the tail, you can take advantage of the mechanical lock to prevent accidental ignition. There is also a sealing O-ring on the threads to protect against water and dust. The Nitecore P20i UV is IP68 certified (2 meters submersible).

At the two poles, for contact with the battery, we find a particular contact system for both negative and positive. The P20i UV has shockproof reverse polarity protection mechanism.

The battery supplied with the Nitecore P20i UV is a protected 21700 (NL2140i with 4,000mAh), patented by Nitecore. It has a two-way output with positive and negative polarity on both ends and a high energy density. Nitecore P20i UV accepts only Nitecore proprietary batteries for the “i” series with double pole both in the head and in the tail.
The Nitecore NL2140i battery is compatible with conventional chargers such as the NITECORE UMS2, UMS4, Ull, U12 and others to charge the 21700 i series batteries. The length of the battery, measured by me, is 76mm.

The Nitecore P20i UV is composed of two separable parts: head with body and tail cap. There are no holes on the tail cap for inserting the lanyard that will be inserted into the Clip.
The tail has a two-switch design, we find the mechanical tactical button to turn the flashlight on or off (on-off) with the “momentary on” function (which can be activated when the flashlight is off). To operate the switch you have to make a fair amount of force and the click is noisy.

On the other hand, the flat electronic (mode) selector with which we have access to the second generation Nitecore “Strobe Ready” technology is almost silent. The Strobe of the P20i UV is accessible both with the torch off and with the torch on and has two channels of frequencies 16Hz to 20Hz, the frequencies change randomly causing stronger dizzying effects.
With the "mode" button we will also change the 4 levels available with the P20i UV.

Some shots with the Nitecore P20i UV near the Nitecore P20i and near other flashlights.


Nitecore P20i UV has two switches in queue and provides 2 user modes for different uses.

- Daily mode (default): In this user mode, there are 4 brightness levels [HIGH (1800 lumens), MID (250 lumens), LOW (35 lumens) and UV] and STROBE mode. The P20i UV will store and re-enter 4 brightness levels or STROBE mode when it is reactivated, unless it has been switched to another user mode.
- Tactical mode: In this user mode, the P20i UV will only store and re-propose the HIGH and STROBE levels as soon as the flashlight is turned on, unless you select a different user mode in the meantime.

Operating Instructions

Tactical Momentary Illumination
Half press and hold the Power Button to turn on the light momentarily. Release to turn it off.

On / Off
On: When the light is off, press the Power Button until a click sound is heard to turn it on.
Off: When the light is on, press the Power Button until a click sound is heard to turn it off.

User Mode Selection
The P20i UV provides 2 user modes for different users and situations.

  • Daily Mode (Default Setting):In this user mode, the P20i UV will memorize and reaccess any of the 3 brightness levels, UV or STROBE Mode when reactivated, unless it has been switched to the other user mode.
  • Tactical Mode: In this user mode, the P20i UV will only memorize and re-access the HIGH Level or STROBE Mode when reactivated, unless it has been switched to the other user mode.
To select a desired user mode:

  1. Ensure the tail cap is fully tightened.
  2. Keep holding the Mode Button (STROBE READY™) on the tail cap and the flashlight will access the STROBE Mode while simultaneously loosening the tail cap.
  3. Once the tail cap has been loosened, the primary white LED will indicate a user mode selected by flashing once for Daily Mode and flashing twice for Tactical Mode.
  4. Release the Mode Button (STROBE READY™) and tighten the tail cap.
Brightness Levels

  • Daily Mode: When the light is on, short press the Mode Button (STROBE READY™) to cycle through the following brightness levels: UV – LOW – MID – HIGH.
  • Tactical Mode: When the light is on, short press the Mode Button (STROBE READY™) to cycle through the following brightness levels: HIGH – MID – LOW – UV.

  • When the light is off in either user mode, press and hold the Mode Button (STROBE READY™) to access the STROBE Mode. Release to turn it off.
  • When the light is on in either user mode, long press the Mode Button (STROBE READY™) to access the STROBE Mode. Short press the Mode Button (STROBE READY™) to return to the previous status, or click the Power Button to turn off the light.
Power Indication
- When the battery is inserted, or the flashlight is disconnected from the power source during the charging process, the power indicator will flash to show the battery voltage (±0.1V).
- When the light is on, the power indicator will indicate the remaining battery power.

  1. Being steadily turned on indicates that the power is above 50%.
  2. Flashing slowly indicates that the power is below 50%.
  3. Flashing quickly indicates that the power is below 10%.
Note: When using two CR123/RCR123 in series, the indicator will show the average voltage between the two batteries. The batteries should be replaced or recharged when the output appears to be dim or the flashlight becomes unresponsive due to low power.

ATR (Advanced Temperature Regulation)
The integrated ATR technology regulates the output of the P20i UV according to the working condition and ambient environment to maintain the optimal performance.


Nitecore P20i UV uses two types of light: White and Ultaviolet.
With the central LED Luminus SST-40-W we have a good beam of white light (6500K), despite the 4 lateral UV LEDs placed in the same parabola of the main LED, the yield of the beam when illuminating from a distance is good with a shade that is not too cold and a really appreciable shot.
With the 4 lateral LEDs we have UV lighting (320 mW, wavelength 365 nm).

Taken from "Esperimentanda"

It is known that UV light can make some otherwise invisible spots visible to the human eye. Ultraviolet waves react with a variety of compounds - including B vitamins, chlorophyll and quinine, blood, urine, saliva and sperm etc. that make their molecules glow in blue, green and other colors.
Currently, there are three levels of UV lamps available to the public: UV-A (315nm to 400nm), UV-B (280nm to 315nm) and UV-C (100nm to 280nm). Ultraviolet "black light" is that associated with wavelengths ranging from about 315 to 400 nanometers, therefore it is produced by UV-A lamps. It is therefore necessary to be very careful in choosing the ultraviolet light source, also because UV-B - and, in particular, UV-C - are much more dangerous for eyes and skin.

Traces visible with "black light"

Those listed below are just some of the biological and non-biological compounds that will be fluorescent in the environment under black light.

Blood residue
Blood residue can appear under black light even when the blood has been washed off. Blood does not glow under black light, but reacts with a chemical that creates fluorescence, so it can be detected after this reaction using ultraviolet light at a crime scene. Blood stains under ultraviolet light appear about 4 times darker than normal, almost black.
However, recent studies have shown that traces of blood in various materials are completely eliminated when washed with detergents containing active oxygen. In this case, the blood cannot even be detected by the various reagents used today in forensic medicine, such as luminol, phenophthalene or the human hemoglobin test.

Human or animal urine
The black light illuminates urine stains, which is useful if you smell cat or dog urine in your home but can't pinpoint where the smell comes from. It is actually a good way to make sure that a bathroom or hotel room is really clean. Urine has a bright yellow or yellow-green light when illuminated by black light. Cat urine, in particular, emits bright light under UV light. Urine glows under a black light mainly because it contains the element phosphorus.

Saliva, semen and vaginal fluids
Since body fluids such as sperm, saliva and vaginal fluids are naturally fluorescent, the use of a black UV light source offers a unique method for their localization. The stains of semen, vaginal fluids and saliva glow a bright yellow or yellow-green under ultraviolet light. However, clothes and bed sheets will also glow and hinder the detection of evidence. It is therefore necessary to tune longer wavelengths to eliminate background interference.

Various substances and foods
Petroleum jelly emits a brilliant blue color under a fluorescent light. The fungus that causes athlete's foot glows orange. Stains on bananas, chlorophyll, highlighters and cotton balls, detergents and detergents, many cosmetics, various plastics, white paper, banknotes, some stamps, some vitamins and certain minerals and gems also shine in the black light. Among the foods, turmeric (a spice), olive oil, canola oil, honey, tonic water and ketchup are fluorescent.

The Runtime were done in a closed environment with an ambient temperature of about 22 °C using the supplied battery, a 4000 mAh protected Nitecore 21700, fully charged.
I would like to clarify that the values expressed by the graphs must be evaluated above all as a reference because they are made with means and conditions different from those used in the laboratory.
Nitecore P20i UV is well regulated. From the initial 1800 lumens and 28500cd, just before the two minutes, we have a sudden drop in brightness to reach about 10500cd after about 3 and a half minutes. This trend is then held for over 140 minutes.
When the battery is low, the notification LED, which is blue, flashes rapidly to indicate that the battery needs to be charged or replaced. The P20i UV is also equipped with the ATR (Advanced Temperature Regulation) module, which regulates its output power adapting to the surrounding environment, maintaining optimal performance.
Note: The "HIGH" level can be recalled until the battery charge is almost exhausted. However, the corresponding exit will be lower than the starting one each time.

Nitecore P20i UV at HIGH level (1800 lumen) without ventilation.

Nitecore P20i UV at HIGH level (1800 lumens) without ventilation for the first 8 minutes.

Nitecore P20i UV at MID level (250 lumens) without ventilation.


Nitecore with the P20i UV adds UV light to the P20i to have an even more performing product while almost completely maintaining the excellent characteristics that I had previously found on the P20i. Always high quality of construction and compactness thanks to the excellent design of the torch. Good levels and autonomy even if I would have added an ultra-low level of 1 lumens or less. The Nitecore is sold complete with accessories to be used immediately. Small limitation the proprietary battery of the i-Generation series but the package includes the adapter for CR123, primary or rechargeable batteries to be used in emergency with some limitations. In conclusion, the Nitecore P20i series remains a solid point in tactical flashlights if you want to have a product, to illuminate, complete and performing.
Thank you for reading the review.

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